Thursday, December 17, 2009

DNA Testing - A Game Changer

These are exciting times in family research for all of us. There are two game changers that are worth talking about. One is DNA testing and the other is Google Books. Today I am going to talk about DNA.

DNA is an abbreviation for deoxyribonucleic acid. The shape of DNA is a double helix and all living things are made up of DNA. Friedrich Miescher first isolated DNA in 1869. The only cells in the human body that do not contain DNA are red blood cells. If the entire DNA in the human body were unwound, it would reach to the moon and back six thousand times. A single cell can contain six to nine feet of DNA. All humans share about ninety-nine percent of the same DNA sequence. It’s the remaining one tenth of a percent that makes us each unique. We all share a considerable amount of DNA with many other species. Our DNA is ninety-eight percent the same as chimpanzees’ and even fifty percent the same as bananas!

DNA makes up our genes. The environment can affect DNA and as a result, environmental factors may result in certain genes expressing or not expressing themselves. In fact, it’s believed that the majority of our genes do not express themselves. It takes about eight hours for a cell to copy its DNA. This copy process must occur before cells divide. Each inch of DNA can store twenty-five gigabytes of information. An entire sequence of DNA is known as a genome. A complete map of the human genome was finished in 2003. Mutations are changes in the DNA sequence and can be caused by exposure to things such as radiation or chemicals. These mutations may lead to an increased risk of disease including cancer. All of DNA’s functions depend on proteins.

DNA testing can also help determine a person’s risk for certain genetic diseases. Paternity tests make use of DNA to determine if a father and child’s DNA make-up are sufficiently similar. Similar tests are available to identify sibling or grandparent relationships. Modern-day forensics also relies heavily on DNA testing to determine if someone was present at a crime scene. It can also help to identify victims of crimes or accidents.